WO2021204652A1

WO2021204652A1 - Optoelectronic component and illumination device

Info

Publication number: WO2021204652A1
Application number: PCT/EP2021/058572
Authority: WO
Inventors: Laura KREINER
Original assignee: Osram Opto Semiconductors Gmbh
Priority date: 2020-04-08
Filing date: 2021-04-01
Publication date: 2021-10-14
Also published as: US20230155085A1; DE112021002249A5

Abstract

In at least one embodiment, the optoelectronic component (10) comprises a semiconductor body (1) with an active region for generating electromagnetic primary radiation, and an exit area (2). The component further comprises an optical element (4, 5, 7), located behind the exit area, for deflecting and/or converting radiation generated in the component, and a dielectric mirror (3) between the exit area and the optical element. The dielectric mirror is permeable to radiation that has a predefined wavelength and is incident at an angle of incidence lying within a predefined first range of angles, while being reflective for radiation that has the predefined wavelength and is incident at an angle of incidence lying within a predefined second range of angles.

Description

description

OPTOELECTRONIC COMPONENT AND LIGHTING DEVICE

An optoelectronic component and a lighting device are specified.

One problem to be solved consists in specifying an optoelectronic component that efficiently emits radiation. Another object to be solved consists in specifying a lighting device with such an optoelectronic component.

These objects are achieved, among other things, by the subjects of the independent claims and claim 14. Advantageous refinements and developments are the subject matter of the further dependent claims and are also evident from the following description and the drawings.

In accordance with at least one embodiment, the optoelectronic component comprises a semiconductor body with an active region for generating electromagnetic primary radiation. In addition, the semiconductor body has an exit area.

The semiconductor body is based, for example, on a III-V compound semiconductor material. The semiconductor material is, for example, a nitride compound semiconductor material such as Al _n In _] __ _nm Ga _m N, or a phosphide compound semiconductor material such as Al _n In _] __ _n _ _m Ga _m P, or an arsenide Compound semiconductor material, such as

Al _n In _] __ _nm Ga _m As or Al _n In _] __ _nm Ga _m AsP, where 0 <n < 1, 0 <m <1 and m + n <1. The semiconductor body can have dopants and additional components. For the sake of simplicity, however, only the essential constituents of the crystal lattice of the semiconductor body, that is to say Al, As, Ga, In, N or P, are given, even if these can be partially replaced and / or supplemented by small amounts of further substances. The semiconductor body is preferably based on AlInGaN.

The active area of the semiconductor body contains in particular at least one pn junction and / or at least one quantum well structure in the form of a single quantum well, SQW for short, or in the form of a multi-quantum well structure, MQW for short. For example, in normal operation, the active area generates electromagnetic primary radiation in the blue, green or red spectral range or in the UV range or in the IR range.

The primary radiation generated during operation is, in particular, incoherent radiation. The component is in particular a light-emitting diode (LED) or a light-emitting diode chip (LED chip).

The exit surface forms a cover surface of the semiconductor body and is formed from the material of the semiconductor body. When the component is operated as intended, a large part, that is to say at least 50% or at least 75% or at least 90%, of the primary radiation emitted by the semiconductor body emerges from the semiconductor body via the exit surface. In particular, more radiation emerges from the semiconductor body via the exit area during operation than enters. For example, occurs at least twice as much, or at least five times as much, or at least emits ten times as much radiation as one. A mirror layer is preferably arranged on a rear side of the semiconductor body opposite the exit surface, which is, for example, reflective for the entire visible spectrum and / or the primary radiation. The mirror layer can comprise a metallic layer and / or a dielectric layer.

The optoelectronic component is, for example, a semiconductor chip or a so-called chip-size package component. Both in the case of a semiconductor chip and in the case of a chip-size package component, its lateral dimensions, measured parallel to a main plane of extent of the semiconductor body, essentially correspond to the lateral dimensions of the semiconductor body. In particular, the lateral dimensions of the component are then at most 20% or at most 10% or at most 5% greater than those of the semiconductor body. Side surfaces of the component running transversely to the main extension plane can have traces of a singulation process which result from a singulation from a wafer assembly. In the case of a chip-size package component, the side surfaces are made of a potting material such as epoxy.

The component can be free of the growth substrate on which the semiconductor body has grown. In particular, the component is a thin-film chip or a component with a thin-film chip.

The component can be pixelated in such a way that the semiconductor body comprises a plurality of individually and independently controllable emission regions (pixels). When operating the Emission regions, primary radiation is emitted via a partial area of the exit surface that is assigned to such an emission region. For example, the semiconductor body is subdivided into at least four or at least 10 or at least 50 or at least 1000 emission regions.

In accordance with at least one embodiment, the optoelectronic component comprises an optical element for deflecting and / or converting radiation generated in the component. The optical element is arranged downstream of the exit surface along the main emission direction of the primary radiation emerging from the exit surface. When viewed from above, the optical element largely or completely covers the exit surface. The optical element is preferably arranged on the exit surface.

The optical element is specifically designed to influence radiation generated in the component. For example, a thickness of the optical element, measured perpendicular to the main extension plane of the semiconductor body, is at least 1/4 or at least 1/2 or at least 1, where 1 is the wavelength at which the primary radiation or the radiation striking the optical element during operation is global Has maximum intensity. The optical element can be a lens or a deflection structure or a conversion element.

In accordance with at least one embodiment, the optoelectronic component comprises a dielectric mirror between the exit surface and the optical element. The dielectric mirror is, for example a periodic structure, i.e. a Bragg mirror, or a non-periodic structure.

The dielectric mirror preferably comprises a plurality, for example at least two or at least four or at least ten or at least 50 or at least 100, dielectric layers which are stacked on top of one another with respect to the exit surface. The dielectric layers of the dielectric mirror are, for example, alternately high refractive and low refractive. The refractive index of a high-index layer differs from that of a low-index layer by at least 0.1 or at least 0.3 or at least 0.5 or at least 1.0. For example, the low refractive index layers have a refractive index of at most 2. The high-index layers have, for example, a refractive index of at least 2.3.

The values for the refractive index are given here for the primary radiation.

For example, the dielectric layers alternate in the dielectric mirror in such a way that a low-refractive layer is located between each two high-index layers, and vice versa. In the case of a periodic structure, the thicknesses of all dielectric layers are the same within the manufacturing tolerance. In the case of a non-periodic structure, the thicknesses of the dielectric layers vary.

The low refractive index layers comprise or consist, for example, of at least one of the following materials: SiOg, SiN, SiON, MgFg. The high-index layers comprise or consist, for example, of at least one of the following materials: NbgOg, TiOg, ZrOg, HfOg, AlgO, TagOg,

ZnO. The thicknesses of the dielectric layers are for example in each case between 10 nm and 300 nm inclusive.

When viewed in a top view, the dielectric mirror and the optical element each largely cover the exit surface or the semiconductor body, for example at least 80% or completely.

In accordance with at least one embodiment, the dielectric mirror is transparent to radiation of a predefined wavelength or a predefined wavelength range which is generated in the component and which strikes the first dielectric mirror at angles of incidence in a predefined first angular range. The dielectric mirror is reflective for radiation of the predetermined wavelength or the predetermined wavelength range which strikes the dielectric mirror with angles of incidence in a predetermined second angular range. The first angular range and the second angular range preferably do not overlap.

Angles of incidence are measured here as an angle to a normal to the dielectric mirror. A normal to a dielectric mirror is to be understood as a normal to the main extension plane of the dielectric mirror.

"Transparent" is understood here and below to mean that an element transmits or lets through at least 75%, preferably at least 90%, particularly preferably at least 99%. "Reflective" is understood to mean that an element preferably more than 75% at least 90%, particularly preferably at least 99% of a radiation is reflected.

The terms "predetermined first angular range" and "predetermined second angular range" refer to the fact that, when designing a dielectric mirror, the angular range in which it is transparent and the angular range in which it is reflective is determined by the selection of the materials of the dielectric layers and the thickness of the dielectric layers can be adjusted precisely and as desired. In this respect, the angular ranges for transmission and reflection can be specified or selected or determined.

The terms “predetermined wavelength” or “predetermined wavelength range” refer to the fact that the above-mentioned angular selectivity of a dielectric mirror can usually only be optimized to a specific wavelength and a specific range around this wavelength. The choice of the thicknesses and materials of the dielectric layers also play a role here. In this respect, when designing a dielectric mirror, a wavelength or a wavelength range can be specified or selected or determined for which the dielectric mirror is to operate in an optimally angle-selective manner.

The predetermined wavelength or the predetermined wavelength range can be a wavelength or a wavelength range in the spectrum of the primary radiation, for example the wavelength at which the intensity of the primary radiation has a maximum. Alternatively, the specified wavelength / wavelength range can also be one Act wavelength / a wavelength range in the spectrum of a radiation that arises from conversion in the component.

In at least one embodiment, the optoelectronic component comprises a semiconductor body with an active region for generating electromagnetic primary radiation and an exit area. Furthermore, the component comprises an optical element arranged downstream of the exit surface for deflecting and / or converting radiation generated in the component, as well as a dielectric mirror between the exit surface and the optical element. The dielectric mirror is transparent to radiation of a predetermined wavelength generated in the component, which strikes at an angle of incidence in a predetermined first angular range, and is reflective for radiation of the predetermined wavelength, which strikes at an angle of incidence in a predetermined second angular range.

In at least one further embodiment of the optoelectronic component, the latter comprises a semiconductor body with an active region for generating electromagnetic primary radiation and an exit area. Furthermore, the component comprises a metal lens arranged downstream of the exit surface and a polarization filter between the metal lens and the exit surface. The metal lens is arranged in particular on the exit surface.

The present invention is based in particular on the knowledge that many optical elements that are used in optoelectronic components often only function optimally if the radiation generated in the component and striking the optical element fulfills certain beam properties. For example, some optical elements are only efficient when the one that hits them Radiation strikes in a narrow range of angles to the normal. For example, other optical elements only work efficiently if the incident radiation is polarized. Some optical elements can only work efficiently if both directional and polarized radiation are incident.

The present invention makes use of the idea of arranging a selection element in the form of a dielectric mirror and / or a polarization filter in front of an optical element in an optoelectronic component. This selection element only lets radiation of a predetermined wavelength through in a predetermined first angular range and / or only lets radiation of a predetermined polarization through. This preselection of the radiation enables the optical element to work more efficiently or optimally.

The component disclosed here is suitable, for example, as a radiation source for visible and invisible light in a headlight, in particular in a headlight of a vehicle, or in a projector or as a radiation source for sensor applications or for the background lighting of a display, for example a smartphone display or a display for a vehicle interior.

According to at least one embodiment, the first angular range comprises all angles of incidence between 0 ° and ex, measured to a normal to the dielectric mirror. The first angular range thus forms a cone with the normal as the axis of rotation and an opening angle of 2 ·. has a value of at most 75 ° or, for example a maximum of 60 ° or a maximum of 45 ° or a maximum of 30 ° or a maximum of 20 ° or a maximum of 10 °. Alternatively or additionally, the value is for example at least 5 ° or at least 10 °.

According to at least one embodiment, the second angular range comprises all angles of incidence of at least β, measured to the normal to the dielectric mirror, where β> applies. Preferably, β is at least 1 ° or at least 5 ° or at least 10 ° greater than a. Alternatively or additionally, ß is at most 10 ° or at most 5 ° greater than a. The second angular range preferably includes all angles of incidence between β and 90 °, inclusive.

According to at least one embodiment, the dielectric mirror has a transmittance of at least 75% or at least 90% or at least 99% for radiation of the predetermined wavelength / the predetermined wavelength range impinging at angles of incidence in the first angular range and a reflectance of at least 75% or at least 90% or at least 99% for radiation of the specified wavelength / the specified wavelength range impinging at angles of incidence in the second angular range. The specified values of the degree of transmission and the degree of reflection for radiation of the specified wavelength / the specified wavelength range apply particularly preferably to all angles of incidence in the respective angular range.

According to at least one embodiment, the optical element comprises a deflection structure. The deflecting structure is designed in such a way that the radiation of the component passing through the deflecting structure is scattered in an x direction and is less or not scattered in a y-direction, perpendicular to the x-direction. The x-direction and y-direction, for example, both run parallel to the

Main plane of extent of the semiconductor body. For example, the deflection structure increases the opening angle of the radiation in the x direction by at least 50% or at least 100% or at least 200%. In the y direction, the opening angle is increased, for example, by a maximum of 50% or a maximum of 20%.

In other words: If the radiation intensity distribution curve is viewed in a section plane perpendicular to the main extension plane of the semiconductor body and parallel to the x-direction, the opening angle of the distribution curve for the radiation immediately after passing through the deflection structure is at least 1.5 times or at least that 2 times or at least 3 times the opening angle of the radiation intensity distribution curve of the radiation immediately before passing through the deflection structure. If, on the other hand, the radiation intensity distribution curve is viewed in a section plane perpendicular to the main extension plane of the semiconductor body and parallel to the y-direction, then the opening angle of the distribution curve of the radiation immediately after passing through the deflection structure is at most 1.5 times or at most 1.2 - times the opening angle immediately before stepping through. The opening angle is understood here to mean the angular range in which the radiation intensity of the radiation is at least 50% of its maximum.

By setting the radiation to a first angular range, a particularly strong asymmetry of the opening angle of the far field in the x-direction and y-direction can be achieved. In fact, in some applications of optoelectronic components, such far-field patterns are desired. One example is the coupling of radiation from an optoelectronic component into a flat waveguide, in which a strongly asymmetrical far field is advantageous.

With the dielectric mirror, the radiation is initially restricted to a first angular range, which enables the radiation to be completely coupled into the narrow side of the waveguide. The deflection structure then fans out the radiation in one spatial direction, with the result that the broadest side of the waveguide is illuminated as homogeneously as possible.

According to at least one embodiment, the deflection structure has a structuring on a scattering side with trenches extending in the y-direction.

The trenches extend in particular in a straight line along the y-direction and preferably over the entire or almost the entire extent of the deflection structure in the y-direction. In each sectional view parallel to the y-direction, the profile of the scattering side is preferably flat within the manufacturing tolerance. In the case of sectional views parallel to the x-direction, on the other hand, the profile of the scattering side is structured with alternating elevations and depressions, the depressions being assigned to the trenches extending in the y-direction. The elevations and depressions, for example, each taper to a point. The heights of the elevations are, for example, between 100 nm and 50 pm, inclusive. On the scattering side, incident radiation is scattered in the x-direction and less or not scattered in the y-direction. The scattering side can be formed on a side of the deflecting structure facing and / or facing away from the semiconductor body. The deflecting structure is preferably formed from a material that is transparent to the radiation generated in the component. For example, the deflection structure is made of glass or silicone or epoxy or plastic or SiOg or NbOg or

TiOg or SiN formed. The deflecting structure is preferably formed in one piece or in one piece.

The scattering side can border on air or can be covered with an encapsulation layer which fills the trenches and is flat and / or smooth on a side facing away from the scattering side. The encapsulation layer preferably has a transparent material with a different refractive index than that of the deflecting structure. The difference in refractive index ensures that it is scattered when passing through the scattering side. The planar and / or flat side of the encapsulation layer simplifies assembly of the component, for example directly on a light guide / waveguide.

Such an optoelectronic component with a dielectric mirror and deflection structure can be produced, for example, in a front-end process at wafer level. A dielectric mirror and then a layer are then deposited on a wafer with an epitaxially grown semiconductor body, the layer then being structured with one-dimensional trenches, for example by lithography. The wafer is then cut up, creating individual optoelectronic components. Alternatively, the deflection structure can also be applied to the semiconductor body in the back-end process. The deflection structure is then produced separately, for example by etching one side of a small glass plate, which is then arranged downstream of the exit surface of the semiconductor body. The dielectric mirror and / or a conversion element can also be applied beforehand to an opposite side of the small glass plate.

According to at least one embodiment, the optical element comprises a metal lens. A metal lens has a structuring in the refractive index in directions parallel to its main direction of extent. The structuring can be periodic or aperiodic. Areas of the same refractive index each have a lateral extent, measured parallel to the main extension plane of the metal lens, of, for example, at most 1 gm and / or at least 2 nm.

The metal lens is arranged in particular on the semiconductor body in such a way that its

Main extension plane runs parallel to that of the semiconductor body. The metal lens has, for example, a thickness, measured perpendicular to its main extension plane, of at most 5 μm or at most 1 μm or at most 500 nm or at most 100 nm.

The metal lens can be a converging lens or a diverging lens. The metal lens can be configured to generate an asymmetrical far field. The metal lens can also be set up in such a way that it generates a structured far field, which can be desired, for example, in IR applications. For example, the metal lens also acts in such a way that it has the Radiation passing through is scattered in the x-direction and less or not scattered in the y-direction. All of the features disclosed in connection with the deflection structure with regard to the opening angle asymmetry in the x and y directions are correspondingly also disclosed for the metal lens.

For example, the metal lens is formed from at least two materials with different refractive indices. The materials are arranged one after the other along the main extension plane, whereby the structuring in the refractive index is formed. For example, one material is SiOg and another material is NbOg. The materials mentioned in connection with the dielectric layers can also be used. As an alternative or in addition, the metal lens can have holes which extend perpendicular to the main extension plane through the metal lens and form regions of a refractive index.

Instead of or in addition to a metal lens, a photonic crystal can also be used.

According to at least one embodiment, a polarization filter, in particular a reflective polarization grating, is arranged between the metal lens and the semiconductor body. The polarization filter is set up to polarize the radiation generated in the component and incident on the polarization filter and to allow radiation of only one polarization direction to pass. The radiation reflected on the polarization filter can be repolarized by scattering processes in the component and then let through the next time it hits the polarization filter. Metal lenses also ensure efficient deflection when the radiation hits the metal lens as directed and / or as polarized as possible. With a directional emission achieved by the dielectric mirror as a basis, a metal lens can also image broadband, white light well in a desired far field. In this respect, the upstream dielectric mirror and / or the upstream polarization filter are advantageous. Metal lenses offer the advantage that they can be made much flatter than conventional lenses, so that the entire component is more compact. In the case of metal lenses, all structures can also be applied in the front-end process, which enables chip-size package components to be manufactured.

In accordance with at least one embodiment, the component comprises a conversion element which is set up to convert radiation generated in the component. For example, the conversion element converts the primary radiation into secondary radiation during operation.

The conversion element comprises or consists of one or more conversion materials. These can be sintered to form a ceramic conversion element or pressed to form a conversion element. Alternatively, the conversion element can comprise a matrix, for example made of silicone, in which the conversion material is embedded and distributed.

The conversion material can be, for example, a garnet or a nitride or an oxide or an oxynitride. Alternatively, the conversion material can also be based on a semiconductor such as CdSe, CdTe, CdS. For example, this includes Conversion material then quantum dots and / or nanoplates made of semiconductor material.

According to at least one embodiment, the optical element comprises the conversion element. That is to say, the dielectric mirror is arranged between the conversion element and the exit surface. During operation, for example, unconverted primary radiation then strikes the dielectric mirror. The predetermined wavelength is then preferably a wavelength for which the primary radiation provides a significant intensity. For example, the predetermined wavelength is then that at which the intensity distribution of the primary radiation has its global maximum.

According to at least one embodiment, the dielectric mirror has a higher degree of transmission for radiation of the predetermined wavelength with large angles of incidence in the first angular range than for radiation of the predetermined wavelength with small angles of incidence in the first angular range. In particular, the transmittance for at least some angles of incidence in the first angular range and greater than 0 ° is greater than at 0 °. For example, the transmittance for all angles of incidence between 0.6 and 0.9 inclusive is greater, for example at least 5% greater, than for all angles of incidence between 0 ° and 0.3 inclusive.

If, for example, the primary radiation with Lambertian distribution is emitted from the exit surface, the primary radiation that has passed through the dielectric mirror has essentially the same intensity / radiation strength for all angles in the first angular range, preferably even with a superelevation at larger angles.

The intensity drops sharply at the transition to the second angular range.

In the case of components with radiation conversion, especially in the case of components emitting white light, the color point depends on the viewing angle. The proportion of converted light (for example yellow light) is typically higher at flat angles than when the lighted area is viewed from the front. The reason for this is the longer optical path length of the primary radiation (for example blue light) through the conversion element and thus a higher absorption for flat emission angles. In the application, however, a uniform color appearance is often desired regardless of the viewing angle.

In the dielectric mirror between the conversion element and the semiconductor body, primary radiation is cut off in the second angular range. In the first angular range, a higher transmission takes place at flatter emission angles (larger angles of incidence) than at steeper emission angles (smaller angles of incidence). This leads to an overcompensation of the stronger absorption of the primary radiation in the conversion element in the case of flatter emission angles and thus to a more homogeneous color locus distribution in the first angular range.

According to at least one embodiment, the conversion element is arranged between the dielectric mirror and the exit surface. During the conversion of radiation generated in the component, in particular the primary radiation, the conversion element generates a Secondary radiation. The conversion element can be set up for full conversion or partial conversion.

According to at least one embodiment, the dielectric mirror is transparent to secondary radiation which strikes the dielectric mirror at angles of incidence in the predetermined first angular range. Likewise, the dielectric mirror can be transparent to primary radiation which strikes the dielectric mirror at angles of incidence in the predetermined first angular range.

According to at least one embodiment, the dielectric mirror is reflective for secondary radiation which strikes the dielectric mirror at angles of incidence in the predetermined second angular range. Likewise, the dielectric mirror can be reflective for primary radiation which strikes the dielectric mirror at angles of incidence in the predetermined second angular range.

According to at least one embodiment, a further dielectric mirror is arranged between the conversion element and the exit surface. Like the dielectric mirror, the further dielectric mirror can have a plurality of dielectric layers. All of the features disclosed in connection with the dielectric mirror are also disclosed for the further dielectric mirror.

In accordance with at least one embodiment, the further dielectric mirror is transparent to primary radiation which strikes the further dielectric mirror at angles of incidence in the predetermined first angular range. In accordance with at least one embodiment, the further dielectric mirror is reflective for primary radiation which strikes the further dielectric mirror in the predefined second angular range.

The further dielectric mirror can be reflective for the secondary radiation at all angles of incidence.

According to at least one embodiment, the exit surface has a structure. For example, the exit surface is roughened. A mean roughness of the exit surface is then, for example, at least 500 nm or at least 1000 nm. The structuring of the exit surface can achieve a redistribution of the radiation reflected by the dielectric mirror or mirrors, so that the next time it hits a dielectric mirror, it may have an angle of incidence meets the respective dielectric mirror in the first angular range.

In accordance with at least one embodiment, a planarization layer is applied to the exit area, which is planar and / or smooth on a side facing away from the semiconductor body. In particular, the planarization layer is applied directly to the exit surface. In particular, the planarization layer is then arranged between the dielectric mirror and the exit surface. The planarization layer preferably comprises a material that is transparent to the radiation generated in the component, in particular the primary radiation or converted radiation, such as silicon dioxide (SiOg)

Planarization layer simplifies and improves the application of the dielectric mirrors. According to at least one embodiment, a small glass plate is arranged between the metal lens and the dielectric mirror or between the metal lens and the polarization filter. The glass plate can be self-supporting. For example, the glass plate has an average thickness of at least 50 gm and / or at most 500 gm.

For the production of the component with metal lens and glass plate, for example, a metal lens designed for the desired far field is produced on a first side of a glass wafer. The dielectric mirror and / or the polarization filter are applied on an opposite, second side. Furthermore, a conversion element can be applied to this second side. The glass wafer is separated into individual glass plates each with a metal lens, a dielectric mirror and / or a polarization filter and, if necessary, with a conversion element. These are then glued onto the exit surfaces of semiconductor bodies. Alternatively, it would also be conceivable to apply the glass wafer with the various elements as a composite to a wafer with an epitaxially grown semiconductor body, and then to separate the glass wafer together with the semiconductor body wafer into individual components.

Instead of forming the polarization filter and / or the dielectric mirror or the conversion element on the second side of the glass wafer, one or more of these elements can also be formed on the exit surface of the semiconductor body, for example already in the front-end process on the wafer, and then the glass wafer is formed or that Glass plate applied to the semiconductor body with the metal lens.

In accordance with at least one embodiment, the component emits white light during operation. In particular, a mixture of the primary radiation and the radiation resulting from conversion forms white light.

Alternatively, however, it is also conceivable that the radiation emitted by the component during operation is radiation in the red and / or infrared spectral range. For example, the primary radiation is in the red or infrared spectral range and the radiation resulting from conversion is in the infrared range. The component is then suitable, for example, as a radiation source in spectrometer or sensor applications.

Next, the lighting device will be given.

In accordance with at least one embodiment, the lighting device comprises an optoelectronic component described here. Furthermore, the component comprises a light guide (also called a waveguide) with a coupling-in side via which radiation coming from the component during operation is coupled into the light guide. For example, the component is attached directly or indirectly to the coupling side.

During operation, the radiation coupled into the light guide is guided along the light guide and possibly decoupled again in a targeted manner. The light guide comprises or consists, for example, of glass or plastic. The light guide is, for example, a solid body. According to at least one embodiment, the light guide is formed in the shape of a plate with two main sides lying opposite one another. The main sides in particular run parallel to one another. The main sides can be flat or curved. The thickness of the light guide, measured as the distance between the main sides, is preferably less than the extent of the main sides in each direction. Extensions of the waveguide along the main sides are, for example, at least five times or at least ten times or at least 20 times as great as the thickness of the light guide. A thickness of the light guide is, for example, at most 1 mm or at most 500 μm. Extensions along the main sides are, for example, at least 1 cm or at least 5 cm.

According to at least one embodiment, the coupling side is formed by a transverse side connecting the main sides.

The transverse side has a smaller area than each of the main sides. For example, the area of the transverse side is at most one fifth or at most one tenth or at most 1/20 the area of the main pages. The transverse side is elongated and preferably rectangular. The main pages can each be rectangular.

During operation, the radiation that has entered via the coupling-in side can be decoupled again via one of the main sides. The lighting device is then particularly suitable as background lighting for a display, for example a smartphone display or a display for a vehicle interior.

For example, the component is one with a deflection structure as described above or a metal lens. The component is then preferably so on Coupling side arranged that the x-direction runs parallel to the main sides or parallel to the longer edge of the transverse side and that the y-direction runs perpendicular to the main sides or parallel to the shorter edge of the transverse side.

The component is in particular smaller than the transverse side / coupling side, so that, viewed in a plan view, the component lies completely within the transverse side. The lighting device preferably comprises a plurality of components as described here, which are arranged one behind the other in a direction parallel to the longer edge of the transverse side and whose radiation is in each case coupled into the light guide via the coupling side.

Further advantages and advantageous configurations and developments of the optoelectronic component and the lighting device emerge from the following exemplary embodiments illustrated in connection with the figures. Identical, identical or identically acting elements are provided with the same reference symbols in the figures. The characters and the

The proportions of the elements shown in the figures are not to be regarded as being to scale. Rather, individual elements, in particular layer thicknesses, can be shown exaggeratedly large for better displayability and / or for better understanding.

Show it:

Figures 1 to 9 exemplary embodiments of the optoelectronic component in different views, FIG. 10 shows an exemplary embodiment for the far field generated by a component,

Figures 11 to 15 embodiments of lighting devices in different views.

FIG. 1 shows a first exemplary embodiment of an optoelectronic component 10 in a cross-sectional view. The component 10 comprises a semiconductor body 1, for example based on AlInGaN, with an active region (not shown). In normal operation, incoherent primary radiation is generated in the active area. In the present case, the primary radiation is, for example, radiation in the blue spectral range.

A dielectric mirror 3 is arranged on an exit surface 2 of the semiconductor body 1. During normal operation of the component 10, a large part of the primary radiation generated by the semiconductor body 1 emerges from the semiconductor body 1 via the exit surface 2. The dielectric mirror 3 is set up in such a way that it is transparent to primary radiation which strikes with angles of incidence in a first angle range between 0 ° and inclusive and for primary radiation which strikes with angles of incidence in a second angle range outside the first angle range (from β to 90 ° ) is reflective. In the present case, the value for example is 30 °. The value for ß is, for example, 35 °.

On the side of the dielectric mirror 3 facing away from the semiconductor body 1, an optical element 4, 5, 7 is arranged, which is set up to deflect and / or convert the radiation passing through. This shows that optical element 4, 5, 7 in particular a thickness of at least a quarter of the wavelength at which the primary radiation has its intensity maximum.

FIG. 2 shows a second exemplary embodiment of the optoelectronic component 10. Here, a conversion element 7 is arranged between the dielectric mirror 3 and the exit surface 2. During operation, the conversion element 7 converts the primary radiation into secondary radiation, for example into light in the yellow to green and / or orange to red spectral range. The dielectric mirror 3 is transparent to secondary radiation which strikes at angles of incidence in the first angular range and is reflective for secondary radiation which strikes at angles of incidence in the second angular range. The dielectric mirror 3 can have the same angular selectivity for the primary radiation. The light passing through the dielectric mirror 3 is in particular a mixture of the primary radiation and the secondary radiation, which results, for example, in white light.

In the present exemplary embodiment, the optical element is a deflection structure 4, for example made of glass or transparent silicone or transparent plastic or SiOg or NbOg or TiOg or SiN, which on a scattering side 40 facing away from the semiconductor body 1 has a structure with it in a Comprises trenches 41 extending in the y-direction. The view in FIG. 2 shows a section perpendicular to the y direction and parallel to an x direction, the profile of the scattering side 40 having elevations and depressions alternating along the x direction.

FIG. 3 shows the component of FIG. 2 in a plan view of the scattering side 40. It can be seen that the trenches are located 41 extend linearly in the y direction and over the entire extent of the deflection structure 4 in this direction.

The effect of the deflecting structure 4 on the radiation passing through is indicated in FIGS. 2 and 3 by the arrows. In the x direction, the radiation that is initially directed or bundled by the mirror 3 and hits the scattering side 40 is scattered by the structuring. In the y direction, the directed radiation essentially retains its directionality.

The third exemplary embodiment in FIG. 4 is similar to that in FIG. 2. In FIG. 2, the scattering side 40 borders on air, as a result of which there is a jump in the refractive index on this side. In FIG. 4, the scattering side 40 borders on an encapsulation layer 42 which fills the trenches 41. The encapsulation layer 42 is selected such that its refractive index differs from that of the deflecting structure 4.

For example, the encapsulation is made of SiOg or SiN. On a side facing away from the deflection structure 4, the encapsulation layer 42 is flat and / or smooth. This allows simple assembly, for example on the coupling side of a light guide.

FIG. 5 shows a fourth exemplary embodiment of the optoelectronic component 10 again in FIG

Cross-sectional view. This is similar to that of FIG. 3. Here, the exit surface 2 of the semiconductor body 1 is additionally structured / roughened. Radiation reflected back by the dielectric mirror 3 can be redistributed by the structuring and, when it next hits the dielectric mirror 3, if appropriate, impinge in the first angular range. A planarization layer 9, for example made of SiOg, which is planar and smooth on a side 9a facing away from the semiconductor body 1, is applied here to the structured exit surface 2. The mean roughness of the side 9a is, for example, less than 1 nm.

A fifth exemplary embodiment of the optoelectronic component 10 is shown in FIG. Compared to the previous exemplary embodiment, this is supplemented by a further dielectric mirror 8. The further dielectric mirror 8 is arranged between the conversion element 7 and the semiconductor body 1. The further dielectric mirror 8 is transparent to primary radiation which strikes at angles of incidence in the first angular range and is reflective for primary radiation which strikes at angles of incidence in the second angular range. The further dielectric mirror 8 can be reflective for the secondary radiation. The dielectric mirror 3 has the angle selectivity described above, at least for the secondary radiation.

The use of two dielectric mirrors offers the advantage that each dielectric mirror can then be optimized for a specific wavelength range (primary radiation or secondary radiation).

FIG. 7 shows a sixth exemplary embodiment of the optoelectronic component 10. This is similar to that of FIG on the other one Polarization filter 6 is arranged. Thanks to the upstream dielectric mirror 3 and the polarization filter 6, polarized, directional white light strikes the metal lens 5. This can then efficiently focus or scatter the light.

The seventh exemplary embodiment of the optoelectronic component 10 shown in FIG. 8, like the fifth exemplary embodiment, comprises a further dielectric mirror 8 in front of the conversion element 7.

Instead of arranging the polarization filter 6 between the glass plate 11 and the dielectric mirror 3, the polarization filter 6 could also be arranged between the dielectric mirror 3 and the semiconductor body 1, in particular between the dielectric mirror 3 and the conversion element 7.

FIG. 9 shows an eighth exemplary embodiment of the optoelectronic component 10, in which the optical element is a conversion element 7. The dielectric mirror 3 has the above-mentioned angle selectivity for the primary radiation. For the secondary radiation produced by conversion by the conversion element 7, the dielectric mirror 3 is reflective at all angles of incidence, for example.

The angular selectivity of the dielectric mirror 3 from FIG. 9 is shown by way of example with reference to FIG. The curve S2 shows the far-field radiation distribution of a Lambert see radiator. On the x-axis, angles between -90 ° and 90 °, measured to a normal to the emission surface of the Lambert radiator, are shown. on the radiation intensity is plotted on the y-axis. As a good approximation, the semiconductor bodies 1 described above form such a Lambertian emitter with the exit surface 2 as the emission surface.

The curve S1 shows the far-field radiation distribution in the event that the dielectric mirror 3 is applied to the emission surface. The dielectric mirror 3 has a high angle selectivity for the primary radiation. In the present case, the dielectric mirror 3 is permeable to radiation with angles of incidence in a first angular range from 0 ° to and reflective for radiation with angles of incidence greater than β. For larger angles of incidence in the first angular range, the transmittance is also higher than for smaller angles of incidence. As a result, the primary radiation passing through the dielectric mirror 3 at the edge of the first angular range has a radiation intensity that is similar, even slightly increased, to that in the center of the first angular range. This creates a more uniform color impression after the conversion, which is almost independent of the viewing angle.

An exemplary embodiment of a lighting device is shown in FIG. A diaphragm 30 is arranged downstream of the component 10 described above, with which the emission angles that lie outside the homogeneous color range are also cut off.

A further exemplary embodiment of a lighting device is shown in FIG. 12, in which a lens 50 is arranged downstream of the component 10, with which the homogeneous color impression is mapped onto a larger angular range. The diaphragm 30 from FIG. 11 and the lens 50 from FIG. 12 can also be combined in one lighting device.

Figures 13 to 15 show an embodiment of a lighting device in different views. The lighting device comprises several optoelectronic components 10, for example those as shown in FIGS. 2 to 8, as well as a light guide 20 with a coupling side 21. The radiation emerging from the components 10 during operation, for example white light, enters via the coupling side 21 the light guide 20 and is then distributed inside the light guide 20.

In the present case, the light guide 20 is designed in the form of a plate and has two opposing main sides which are connected to one another by the coupling-in side 21 and which are each significantly larger than the coupling-in side 21. The coupled-in radiation is preferably coupled out homogeneously via one or both main sides. The lighting device is, for example, a display backlight.

As can be seen from FIG. 14, the coupling side 21 is rectangular and elongated. The components 10 are arranged one behind the other and at a distance from one another along the longer edge of the coupling side 21. The x direction along which the radiation emitted by the components 10 is scattered runs parallel to the longer edge. The y-direction, along which the radiation emitted by the components 10 has a small opening angle, runs parallel to the shorter edge of the Coupling side 21. In this way, the radiation emitted by the components 10 is efficiently coupled into the plate-shaped light guide 20. The beam path or the beam spot of a component 10 is indicated in FIGS. 13 to 15 by the dashed lines.

The description on the basis of the exemplary embodiments is not restricted to the invention. Rather, the invention encompasses any new feature and any combination of

Features, which in particular includes any combination of features in the patent claims, even if these features or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.

List of reference symbols

1 semiconductor body

2 exit area

3 dielectric mirror

4 optical element / deflection structure

5 optical element / metal lens

6 polarizing filters

7 optical element / conversion element

8 more dielectric mirrors

9 planarization layer

9a side of the planarization layer

10 optoelectronic component

11 glass plates

20 light guides

21 Coupling side

30 aperture

40 spreading side

41 ditch

42 encapsulation layer

50 lens angle ß angle

51 curve

52 curve

Claims

1. An optoelectronic component (10) comprising

- A semiconductor body (1) with an active area for generating electromagnetic primary radiation and an exit surface (2),

- An optical element (4, 5, 7) arranged downstream of the exit surface (2) for deflecting and / or converting radiation generated in the component (10),

- A dielectric mirror (3) between the exit surface (2) and the optical element (4, 5, 7), wherein

- The dielectric mirror (3) is transparent to radiation of a predetermined wavelength generated in the component, which strikes at angles of incidence in a predetermined first angular range, and is reflective for radiation of the predetermined wavelength, which strikes at angles of incidence in a predetermined second angular range.

2. The optoelectronic component (10) according to claim 1, wherein the first angular range includes all angles of incidence between 0 ° and, measured to a normal to the dielectric mirror (3), the second angular range all angles of incidence of at least β, measured to the normal comprises the dielectric mirror (3), where β h oc applies.

3. The optoelectronic component (10) according to claim 2, wherein the optical element comprises a deflection structure (4) which is designed such that the radiation of the component (10) passing through the deflection structure (4) is scattered in an x-direction and in a y- Direction, perpendicular to the x-direction, is less or not scattered.

4. The optoelectronic component (10) according to claim 3, wherein the deflecting structure (4) has a structuring on a scattering side (40) with trenches (41) extending in the y-direction.

5. The optoelectronic component (10) according to claim 1 or 2, wherein the optical element comprises a metal lens (5).

6. Optoelectronic component (10) according to claim 5, wherein a polarization filter (6) is arranged between the metal lens (5) and the semiconductor body (1).

7. The optoelectronic component (10) according to any one of the preceding claims, wherein the component (10) comprises a conversion element (7) which is set up to convert radiation generated in the component (10).

8. Optoelectronic component (10) according to claim 7, wherein

- the optical element comprises the conversion element (7),

- The dielectric mirror (3) for radiation of the predetermined wavelength with large angles of incidence in the first angular range has a higher degree of transmission than for radiation of the predetermined wavelength with small angles of incidence in the first angular range.

9. The optoelectronic component (10) according to claim 7, wherein the conversion element (7) is arranged between the dielectric mirror (3) and the exit surface (2), the conversion element (7) during the conversion of im Component generated radiation generates secondary radiation,

- the dielectric mirror (3) is transparent to secondary radiation which strikes the dielectric mirror (3) at angles of incidence in the predetermined first angular range,

- The dielectric mirror (3) is reflective for secondary radiation which strikes the dielectric mirror (3) at angles of incidence in the predetermined second angular range.

10. Optoelectronic component (10) according to claim 9, wherein a further dielectric mirror (8) is arranged between the conversion element (7) and the exit surface (2),

- the further dielectric mirror (8) is transparent to primary radiation which strikes the further dielectric mirror (8) at angles of incidence in the predetermined first angular range,

- The further dielectric mirror (8) is reflective for primary radiation which strikes the further dielectric mirror (8) in the predetermined second angular range.

11. Optoelectronic component (10) according to one of the preceding claims, wherein the exit surface (2) has a structuring, on the exit surface (2) a planarization layer (9) is applied, which on a side (9a) facing away from the semiconductor body (1) is planar.

12. Optoelectronic component (10) according to claim 5 or one of claims 6 to 11 in their respective reference back to claim 5, wherein a glass plate (11) is arranged between the metal lens (5) and the dielectric mirror (3).

13. Optoelectronic component (10) according to one of the preceding claims, wherein the component (10) emits white light during operation.

14. Lighting device comprising

- An optoelectronic component (10) according to one of the preceding claims,

- A light guide (20) with a coupling side (21) via which radiation coming from the component (10) during operation is coupled into the light guide (20).

15. Lighting device according to claim 14, wherein

- The light guide (20) is formed like a plate with two opposite main sides,

- The coupling side (21) is formed by a transverse side connecting the main sides, the area of which is smaller than that of the main sides.

16. An optoelectronic component (10) comprising

- A metal lens (5) arranged downstream of the exit surface (2),

- A polarization filter (6) between the metal lens (5) and the exit surface (2).